Another failed G0704 motor controller - Page 2


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Thread: Another failed G0704 motor controller

  1. #13
    Community Moderator Al_The_Man's Avatar
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    Also Baldor offer the identical units, just relabled.
    Al.

    CNC, Mechatronics Integration and Custom Machine Design

    “Logic will get you from A to B. Imagination will take you everywhere.”
    Albert E.


  2. #14
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    I believe Hoss once said that the controller was a knockoff of the KBC-125 which is basically the same as the KBMM-125. The KBMM just has integrated fuse holders and i believe allows you to set decel time in addition to accel time.



  3. #15
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    Hy,
    this really looks like a 1:1 knock off of a KBLC motor controller. I know because I have one sitting on my shelf. The blown SCRs are no problem at all, solder in equivalent parts wth a little more headroom for overvoltage. The ones blown are good for 400V/10A and voltage spikes may kill them.
    Tecor S8025 will do, digikey sells them.. As someone else already said, the other three legged components are D6025l, fast diodes with three legs.
    There´s not much the SCRs can take down with them, the power circuit is isolated form the rest of the circuit by the small transformer that can be seen on the left side in the picture.
    In case you don´t want to mess with it, send it to John Gerling, he repairs DC drives at good prices and is really fair and honest.

    What else? Get some heatsink compound, as it seems the parts are mounted dry on the heatsink. Check your secondary connections, in case you have a short circuit or a loose cable between controller and motor this may cause problems. Check if one of the brushes is stuck, too.

    Cheers,
    Johann



  4. #16
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    I called Grizzly today, gave them the story. Seem to be some confusion on which control board it was in his manual. He wasn’t sure it was the motor controller; I told him I was positive it’s the motor controller. Anyway, it had to be forwarded to the electrical guy that should call me tomorrow.

    Thanks for the advice on repairing the controller. If it looks like Grizzly is going to take a while with the replacement, I may give swapping the SCRs a try. Right now I’m thinking I need to just get the mill running so I can make mounts for something better. Figured a while back that I would wait till stock setup crapped out before going to something bigger. I’d like to get a 1.5 HP motor to help push the face mill along without getting too warm after only a few passes.



  5. #17
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    Talked to the Grizzly electrical guy today. He said the controllers are backordered till May, which isn’t good. He also asked me to test the motor with a 12v car battery charger, just to make sure the motor wasn’t the cause. So I gave it a try this evening, the motor turns but seems to vibrate a lot like it was greatly out of balance. I guess this from the really low voltage or maybe the charger sends out a pulse of some kind.



  6. #18
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    I just fried my second motor 30 minutes ago but the motor controller board looks fine this time.

    Grizzly sent me a replacement motor and board last time but it took 3 weeks to get there... ridiculous.

    I'm going to try and demand that they upgrade me to another motor as I don't think I should be responsible for swapping these out every other month or paying for an upgraded motor from an outside source and doing the work required to fit it on the machine. Not to mention that my warranty will be up in a few months and I'm not very confident the stock replacement will last long.

    Tech support is already closed for the day... will call tomorrow.

    -Dave


  7. #19
    Registered Thomasn's Avatar
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    I'm waiting on my second motor and controller myself. I got an email Feb 21 that they were on backorder, but it did not say when they would arrive. I will say that so far they have been very good about replacing any parts that have failed without any hesitation.



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    I was told today that Grizzly is working on addressing the issue and will be upgrading/replacing the motor type soon. In the meantime, I had to just order another stock replacement and am unaware on when that is available to ship until they send me an e-mail confirmation.

    -Dave


  9. #21
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    I’m not going to wait on Grizzly, got things to make. I ordered a KBMM-125 yesterday. Should be an easy replace to get the mill running.



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    Quote Originally Posted by SgtSpyder View Post
    I’m not going to wait on Grizzly, got things to make. I ordered a KBMM-125 yesterday. Should be an easy replace to get the mill running.
    Mine has been working perfectly. Now I am just holding onto the grizzly one as a spare in case of emergency.



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    Got the KBMM-125 this week, going to put in tomorrow. I’ve been looking over the Grizzly wiring diagrams and it doesn’t look like they have the tach signal inputted back in too the SCR controller. That was a little surprising, I’d like to bring the tach signal in to the KBMM-125 but the manual seems to lack some of the info about the sensor. Does anyone have details on the sensor?



  12. #24
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    Wired up the KBMM-125 today, didn’t go well. Keep blowing fuses to the main board. The motor spins, just not very fast. Pulled out the meter, best the voltage the controller could do to the motor was 18vdc. But at that voltage, amperage was hitting the 10 amp current limit I set at the KBMM-125 trimpot. I’m thinking there is no way this motor should be pulling that kind of amperage when free spinning with no load.
    Looks like I’m calling grizzly tomorrow and see about getting a new motor.



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Another failed G0704 motor controller
Another failed G0704 motor controller